Back-stop for elevator-heads.



F. R. MGQUEEN. BACK STOP FOR ELEVATOR HEADS.

APPLICATION FILED 1111.11, 1909.

Patented Feb. 21, 1911.

2 SHEETS-SHEET 1.

F. R. MGQUEEN. BACK STOP FOR ELEVATOR HEADS. APPLICATION FILED JAN. 11, 1909. 1

Patented Feb. 21', 1911.

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STATES? ATEN ICE rnvmrenfnqaonnn, or mrrmneroms, MINNESOTA. v I

I To

i Be it known that I, FINLAY R. McQueen,-

,g of Minneapolis, Hennepin county, Minne- ,sota, have lnvented certain new and useful Improvements in "Back-Stops for Elevator- Heads, f which the-following- 'is a specil fication.

This invention relates to improvements in devices designed to prevent a: backward. movement ofthe head pulley of a grain elevator,.andthe objects I have in view are to provide .a simple device of this charactera that can-be readil applied to any elevator head-shaft Sand wi-ich will effectually preevent any backward movement of the pulleyand shaft, which is liable to. occur when the elevator'is stopped by reason of the down- Y ward pull of the loaded side of.the elevator but.

The invention consists generally infihe 1 constructions and combinations, hereinafter view of an ,elevatorhead having my im-" proved back-stop applied thereto. Fig.2 is

described and, the claims. j e. j

In "the accom anying drawings, forming part of this specification; Figure .1 is a plan a side elevation of the same, partly broken away. Fig. 3is a detail plan of the mecha= nismconstituting. the elevator-stop. Fig. 4

- is a side elevation of the same.

3 Inthedrawings, 2 represents the supporting barsor timbers of a grain elevator-havi ing mountedythereon, in suitable boxes 3, a head-shaft 4, carrying a head-pulley 5. The

elevator-belt 6, provided with a series of buckets 7, passes over this head-pulley-in the usual way and all these parts may be of any ordinary or preferred construction. The shaftg t isdriven by any suitable means, preferably by a suitable electric motor (not shown). It will be'understood that when 'the device is in operation, the buckets on the up-side of the beltare loaded with grain and as these buckets pass over the top of the head-pulley, they empty theirload into a spout hopper or receptacle,.suitably placed to receive it. The buckets on the upside of the belt are, therefore, vweighted with grain, while those on the down-side are empty. If, for any reason, the elevator is stopped when the buckets on the up-side are loaded, the weight of the grain in these buckets tends to cause a reverse motion of the belt and head-pulley and this will often create serious damage'in the mechanism. To obparticularly pointed out in A I 1 w pma mament; Patente'a'reb. 21,1911. a pimt'ioninieaoanuar 11,1aoe. seriarn 471,613,

. viate this-objection, provide .upon theshaft 4, .a suitable disk 8 having,preferably,

a series of centrally disposed ratchet notches Band I mount in uprights 10, 'on a suitable supporting frame 11, a short shaft 12 This shaft is capable of rocking in its bearings and it has secured to it, in any suitable manner, preferably by suitable set-screws 13, the two projecting frames 14. Each of these frames is provided with'suitable ways 15 on which are arrangedthe bearing blocks 16 capable of sliding freely upon said ways. The outer ends of each-frame are connected proper al-inementof .the'parts of eaclrframe may be secured so as to 1118111'6 the free movement of each block 16 upon the ways 15.

Pders ofthe ratchet are supported, not only 5 at the" base, but on each side, and the outer "faces of the shoulders are flush substantially with the friction surfaces on each side of the notches. This construction adapts the device as a backstop for an elevator head where an ordinary ratchet gear with v.the teeth supported only at the base would be stripped off by the dog, owing to the excessive strain to which the-back stop is i subjected when it is called into operation by the backward movement of the elevator. jFor ordinary purposes, the well known: ratchet mechanism would suffice, but as a {back stop for an elevator head where the :meohanism-may he suddenly subjected to a load in tons, it is evident that something fmore than an ordinary ratchet must be em iployed. Furthermore, .by providing the iratchet notches in the center of the disk and the frictionsurfaces on each side,I am able to equalize the strain, distributing it uniformly through-the disk and shaft and theother back stop mechanism.

A suitable spring 20 is provided for each block 16.' These springs are held in position b a the lugs 21 on the blocks 16 and 22 on the inner part of the frame 14, and these springs tend to move the blocks 16 toward the outer end--of said frame 14. Mounted in the blocks 16 is a friction Wheel 23. The surface of this wheel is held in contact with the disk 8 by the springs 20. Secured upon the shaft 12, justabove the friction wheel 23, is a dog or pawl 25, the free end of which by a suitable bolt 17 having adjusting nuts" .18 and 19. By. means of these bolts, the

- tion wheel 23 is moved upward tact therewith of the surface of the disk 8 so that said wheel and the dog 25 stand in the. position shown by full lines in Fig. 2

and by dotted lines in Fig. 4: Should,

however, the' head pulley start in a reverse direction, the'frictional contact of the disk Swith the surface of the friction wheel 23 will cause said wheels, and the parts controlled thereby,.to move downward into the suitable in anner.

position shown by full lines in Fi 4 and the end of the dog or pawl 25 wil en age one of the ratchet notches in the dis 8, thereby stopping said head-pulley and reventing reverse movement of said pu ey and belt.

The frame 11 may be mounted in 'any\ I have here shown this frame nr'untedupon' a plate 26 and this plate is secured upon suitable cross-bars 27. The frame 11 is secured upon the plate 26 by bolts- 28' and iscapable of adjustment thereon, said adjustment being secured by means of suitable adjustin screws 29. I do not, however, limit myse f to the details of the construction herein shown and described, or to 'the details of the' means for supporting and adjusting the friction pulley. and parts controlled thereby.

I claim as my invention: 1. The combination, with a shaft and adisk having peripheral notches mounted thereon, of a pivoted frame, blocks slidable therein, means for alining the parts of said,

i frame and permitting the free movement of said blocks, a friction wheel journaled in said blocks, means for yieldingly holding said wheel and blocks toward said disk, a pivoted dog controlled by said wheel, said dog engaging said ratchet teeth when said' disk is revolved in one direction and being forced out of the pathof said teeth when said disk is revolved in the opposite direction.

2. A back stop for elevator heads comprising a shaft, a disk mounted thereon having centrally arranged ratchet notches in its periphery, and peripheral friction surfaces on each side of said notches, a spring actuated friction wheel arran ed to contact with both of said friction sur aces and a dog or pawlcontrolled by said wheel and ada ted to engage said notches between said ricv tion surfaces as said disk rotates in one difaces and a dogor pawl controlled by said wheel and adapted to'be held by said-wheel I out of contact with said notches as said disk rotates in one direction and be brought into contact therewith as said disk rotates in the other direction.

4. A back stop for elevator heads comprising a shaft, a disk mounted thereon having shroudedratchet notches in its periphery, said disk having friction surfaces on each side of saidnotches, the faces of said surfaces being flush substantially with the outer faces of the shoulders formed by said notches, a spring actuated friction wheel arranged to contact with both of said friction surfaces and a dog controlled by said wheel and adapted to be held thereby out' of contact with said notches as said disk r0- tates in one direction and be broughtinto contact therewith as said disk rotates in the other direction, the pressure of said dog and friction wheelbeing equally distributed on said disk and shaft.

5. A back stop' for elevator heads comprising a shaft, a disk having a shrouded ratchet in its periphery and aspring actuated friction wheel arranged to contact with said periphery. a dog or pawl controlled by said wheel and adapted to be held thereby outof contact with said ratchet as said disk rotates in one direction and be brought into contact therewith as said disk rotates in'the myhand this 28th day of December 1908.

FINLAY R. MCQUEEN.

Witnesses:

J. A. BYINGTON, v G. HANSON. 

